Ruto will win because his competition is wakina maDVD, Kalonzo, Mutua and possibly even Odinga. Ruto strategy should be to appear weak so they don't pull a kibaki by uniting behind one candidate. That is only threat I see - a united opposition and less enthusiatic gema (as one would expect). Of course Ruto learnt from the best so - he'll be instigating the likes of Mutua to ran against Kalonzo - the likes of Joho to ran - couple of Luhyas - and maybe even someone to challenge Raila in Luo Nyanza. Within GEMA - if they cannot support Ruto 100% - then best bet is for the vote to be splinterred - so no strong candidate - meru standing there - a tharaka - a muranga - a nyeri.
Plan A of course is to get Moi's KANU constituency of 90s - Kamatusa(nearly 20% of national vote)+somalis+small tribes+coast should already get Ruto past 30%. His biggest weakness right now is coast..they are still stuck with Raila...Ruto has to win the mijikenda votes without giving them DP or something big ....that leaves him needing about 15% - which he can make deal with any of BIG FOUR (GEMA,LUO,Kamba, Luhya).
Plan B is to imagine Jubilee coalition will remain intact - because it doesn't make sense to break a winning coalition.
All in all the biggest threat to Ruto remain Raila - he has to figure a way to divide NASA now - I'd give something to Wetangula or MadDVD or Kalonzo - but not all of them - just one or two - Wetangula is easy pick - Bukusu are already half-way in Jubilee - fire Eugene Wamalwa and hire Wetangula - let Mutua loose on Kalonzo - maDVD will never get out of Maragoliland. And double down on Joho - until he let off the mijikenda. Crash him financially.
Ruto is very likely to be the 5th president of Kenya.
S - Jubilee behemoth
W - polarizing persona
O - new tribal alliances
T - betrayal by Gema
Odds: 70%